A backlight located at the back side of a liquid crystal display panel emits light during an operation of a liquid crystal display device, and the emitted light passes through the display panel and then is observed by human eyes. Backlights can be categorized into direct-type backlights and side-edge type backlights, and the direct-type backlights are typically used in large-size liquid crystal displays.
The direct-type backlight is a backlight that provides a plurality of light sources at the back side of the liquid crystal display, and generally there is a diffuser plate provided between the light sources and the display panel to diffuse the light emitted by the light sources uniformly, so that the light emitted by the plurality of light sources can irradiate the display panel uniformly.
What shown in FIG. 1 is a schematic view of the structure of an existing diffuser plate. An upper film sheet layer 2, a middle film sheet layer 3 and a lower film sheet layer 4 are generally provided on a diffuser plate 1, so that the light emitted by the light sources can irradiate the liquid crystal display panel more uniformly. However, because the number of the light sources in a backlight module is limited and a distance exists between these light sources, the light irradiated on the display panel is not uniform in intensity, thereby causing poor quality of the displayed screen. On the other hand, the film layers provided on the diffuser plate easily wrinkle or warp due to being affected by environmental factors, so that the screen displayed on the display panel is not uniform, thereby causing undesirable effects such as Moire fringes.
Thus, how to enable the light emitted by the light sources to irradiate the display panel more uniformly is a technical problem need to be solved in the art.